Flora

Trees and plants are the living landscape of your settlement. They grow through stages, develop beauty that inspires elves, and the oldest among them can become notable landmarks -- named trees with histories and the power to form deep bonds with individual elves. The flora system generates 19 procedural species across 8 families at world creation, each with unique aesthetic properties that interact with your elves' cultural values.

Overview

Flora operates on three layers that connect the natural world to elf culture:

• Notable flora -- trees that earn names and histories through age, hardship, or community significance. Notable trees become landmarks that elves bond with (see Tree Bonds).
• Species preference -- elves develop affinities for specific tree species through exposure, which amplifies their nature inspiration when near preferred species.
• Flora beauty -- each tree contributes beauty to its surroundings based on species, season, time of day, and how well the tree's aesthetic aligns with a nearby elf's cultural values.

Notable Flora

How Promotion Works

A tree becomes notable when it meets any one of these criteria:

When a tree is promoted, it receives a unique name and begins tracking its history. A TreeBecameNotable event appears in the event log with the tree's name and the reason for promotion.

Source: crates/er-sim/src/sim/flora_systems.rs, flora_notable_system.

Names and History

Notable trees are named in the format "The [Adjective] [Species] of [Zone]" -- for example, "The Whispering Silverbell of the Eastern Glade." The adjective is drawn from a pool of 10:

Great, Elder, Whispering, Ancient, Silver, Twilight, Starlit, Hollow, Sentinel, Mossy

Each notable tree maintains a TreeHistory that records significant events in its life:

Source: crates/er-sim/src/sim/flora.rs, TreeHistory, TreeEvent.

Species Preference

Exposure and Affinity

Elves develop affinities for tree species through proximity. The species preference system runs every 50 ticks and checks a 3-tile Manhattan radius around each elf:

• Base exposure: 50 ticks accumulated per cycle for each nearby species.
• Aesthetic alignment bonus: If a species' aesthetic emphasis matches the elf's dominant aesthetic axis, exposure is doubled (100 ticks per cycle).
• Preference threshold: A species becomes preferred after 200 ticks of accumulated exposure.
• Maximum preferences: Each elf can prefer at most 2 species simultaneously.

Nature Inspiration

When an elf is near a preferred species, they receive +1 nature inspiration (soft-capped at 100). This stacks with other inspiration sources and creates a feedback loop: elves who spend time near trees develop preferences, which then make those trees more inspiring, which draws the elf back.

Source: crates/er-sim/src/sim/flora_systems.rs, species_preference_system.

Flora Beauty

Calculation

Each tree's beauty contribution is computed from four components:

Total range: -2 to +12.

Base beauty by composition role:

Seasonal modifiers:

Aesthetic alignment scales with the species' base beauty. When an elf's dominant aesthetic axis aligns with the species' emphasis, the bonus is beauty + 1 (ranging from +1 to +5). A neutral elf receives no modifier. When the elf's aesthetics actively oppose the species' emphasis, the penalty is -(beauty / 2) clamped to at least -1 (ranging from -1 to -2).

This means a Heartwood tree (structure + tradition emphasis) looks significantly more beautiful to a structured, traditional elf than to an elf who values emotion and social freedom -- and vice versa for Windcatcher trees.

Source: crates/er-sim/src/sim/flora_systems.rs, flora_beauty_contribution; crates/er-sim/src/sim/flora_gen.rs, generate_aesthetic_lookup.

Flora Species

At world generation, 19 species are created across 8 families. Each family has a distinct growth form, leaf type, and aesthetic emphasis that determines how its species interact with elf culture.

Within each family, individual species vary in soil preference, growth rate, beauty, and seasonal behavior. Species names are procedurally generated from family-specific adjective and core word pools (e.g., a Heartwood species might be "Silver Oak" or "Amber Maple").

Source: crates/er-sim/src/sim/flora_gen.rs, FAMILIES, generate_species_database.

Interactions

• Tree Bonds -- notable trees form bonds with nearby elves, creating deep social connections to the landscape.
• Seasons & Weather -- seasonal phase affects flora beauty modifiers. Shedding (autumn) is the most beautiful season; bare and dormant trees lose appeal.
• Inspiration -- flora beauty and species preference both contribute to nature inspiration, which feeds into compositions.
• Favorite Places -- when 3+ elves designate the same tile as a favorite place, any tree there becomes a notable flora promotion candidate.
• Hydrology -- drought conditions (zero moisture) can trigger notable promotion for mature trees that survive.

Tips

• Autumn is art season. The Shedding phase gives +2 beauty to all deciduous trees. Combined with aesthetic alignment, a traditional elf near a Heartwood tree in autumn can receive +11 beauty contribution. Schedule revels accordingly.

• Match elves to trees. An elf's dominant aesthetic axis determines which species look beautiful to them. Structured elves thrive near Heartwood and Ironbark; emotional elves near Weepwater and Silverleaf. Check the Aesthetic Position panel to find good matches.

• Species preference rewards loyalty. An elf near a preferred species gets +1 nature inspiration per check. Two preferred species cover more ground. Since aesthetic alignment doubles exposure gain, elves naturally prefer species that match their values -- but diverse exposure can build unexpected affinities.

• Notable trees are landmarks. Once a tree becomes notable, it can form bonds with elves. Trees promoted through community significance (3+ favorite places) tend to be near the settlement center, making them natural gathering points. Trees promoted through drought survival may be in harsh locations but carry stories of resilience.